A very rare cause of continuous murmur and coronary ischemia: high-flow coronary-to-pulmonary artery fistula.

A 52-year-old woman presented with complaints of chest discomfort and angina radiating to the neck and left arm on exertion. She reported that the severity of angina was increasing after sublingual nitrate intake. Coronary angiography showed a high-flow fistula between the left main coronary artery and pulmonary artery. Left coronary arteries were normal, but there was a stenotic lesion in the right coronary artery. Coronary artery fistula was ligated successfully under bypass surgery. It was thought that the severity of myocardial ischemia caused by the high-flow fistula was aggravated by sublingual nitrate due to coronary steal phenomenon.